Conventionally, a supported catalyst using metal oxides as a support has been prepared by a method in which a metal salt solution was slowly dropped in the metal oxide support synthesized at a pre-formed commercial or laboratory level and then subjected to drying and supporting.
However, according to the above conventional method, the pore volume and the effective surface area of the metal oxide support have limited the amount of metal salt that can be uniformly supported on the metal oxide support.
To overcome the above-described problems recently, there were made studies for uniformly supporting a nano-catalyst on the surface of carbon materials through an incipient wet impregnation method and a repeated oxidizing and calcining process, but in the course of the preparation, the catalyst was prepared through the incipient wet impregnation method and the repeated oxidizing and calcining process, and thus there were disadvantages in that the preparation procedures are complicated (see, Korean Patent Application Laid-open No. 10-2012-0019524).
If a high concentration of salt is supported on a metal oxide support with small pores using a conventional wet impregnation method, it would take a long time. If a metal salt is supported by the melt impregnation process which has been developed recently, the metal salt can be more easily supported on the support in a well-dispersed state. However, since such a method also uses the pre-formed metal oxide support, the amount of salt that can be ultimately supported is limited (see, de Jong et al., J. Am. Chem. Soc., 2010, 132, 18318-18325).
In the traditionally known supporting method including the above-mentioned method, it was difficult to support metal particles on the support structure at a high concentration. Especially when supporting the particles at a high concentration, it caused a problem in that the size of particles was increased and the stability was decreased.
In order to ensure a high dispersibility and stability of the particles, complicated processes are required for synthesizing the advantageous support in the dispersibility and stability or the catalytic reaction must be restrictively conducted under a low temperature of 200° C. or less. However, these methods have problems such as a limited pore volume of the support, and an influence of the support, which occupies much weight and space, upon calcination. Although it is possible to apply a substance with a very large pore volume in order to solve these problems, this is not a fundamental solution.